This is the Shaka engine's chrome, opt-in under Settings › Video player engine. The default engine, video.js, keeps its stock skin tinted yellow: #FDCE45 icons and progress on a 70% black bar, a round yellow-ringed play button, current and remaining time, and a playback-rate menu.

Shaka's chrome sits on a bottom scrim with fixed on-video whites and Phosphor icons. No title on the video; the file page names it, and app.put.io shows names with dots as spaces.

The subtitle popover is a theme surface anchored above the control bar: Off, then the file's tracks; the active one carries a yellow check. Settings opens the same menu with speed and subtitle style.

Buffering shows a single spinner after 300ms, so short seeks never flash it. The chrome stays put.